This invention relates to a cassette loader which achieves increased tape loading efficiency by performing certain steps to different cassettes simultaneously. This is made possible by very closely controlling the position of the cassette at different times during processing with reference to other machine elements.
High speed automatic cassette loaders are known. Representative Patents disclosing such loaders are U.S. Pat. No. 4061286 (King, Sr. et al), U.S. Pat. No. 3997123 (King), U.S. Pat. No. 381434 (Bennett) and U.S. Pat. No. 4332355 (Zophy). As used in this application the term "cassette" refers to an industry standard audio cassette such as are shown in the drawings. See, e.g., FIGS. 5B and 5C. Such cassettes are formed of a pair of shell halves which are secured together by glue, screws, sonic welding or other means to form the body of the cassette. A pair of hubs are positioned within the shell halves 12, 13 and are designed to freely rotate. A length of leader tape, about 70 cm., is attached by its opposite ends to the hubs. Thus, as used in the cassette loader the cassette is already loaded with the leader tape. Cassette has a pair of capstan holes and a pair of reference holes on both sides, i.e., in both shell halves. The bottom of the cassette is open to permit access by record and playback heads, drive capstans, etc.
In the audio industry these cassettes are referred to as "C-0" cassettes since in this form the cassette has "zero" minutes of recorded material. The purpose of the cassette loader is to load a predetermined length of magnetic tape into the cassette after the cassette shell has been assembled with the hubs and leader tape inside the cassette shell.
There are several important steps involved in properly loading a cassette, including equalizing and extracting the leader tape in preparation for splicing the leader tape to a length of magnetic tape which is to be wound into the cassette. In order for the leader tape to be rapidly pulled out of the cassette without jerking, tangling or perhaps breaking, it is necessary to wind all of the leader tape onto the right side hub. This positions the leader tape so that when it is extracted from the cassette and carried to the splice block, it does not have to pass around a very sharp angle, which would be the case if any of the leader tape were wound around the left hand hub. By winding the leader tape onto the right-hand hub, the leader tape is pulled evenly and at a very shallow angle towards the splice block. In addition, the length of "dead" time at the beginning and end of each side of the cassette is about the same. Without equalization, the length of time between the end of the recorded material and the end of the cassette is very short in one direction of play and very long in the other direction. The end of the leader tape attached to the left-hand hub remains stationary.
All of the loop of the leader tape is formed from tape pulled from the right-hand hub as the leader tape doubles. In prior art processes, the step is carried out before the cassette is wound with magnetic tape. The same is true of the invention described below for the same cassette. However, another cassette which has already been equalized is being simultaneously loaded with magnetic tape.
Another important step is leader extraction. This occurs after equalization and must be carefully and accurately performed if the cassette is to be processed properly.
The present invention provides a structural framework on the cassette loader which enables the cassette to be positively and precisely controlled at every step of the process.